HALT + HASS WHITE PAPER. Advanced Input Systems HALT + HASS LASER-MARKING SEALING BACKLIGHTING USB

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1 We make the input devices that control the OEM products that operate the world. (Highly Accelerated Life Testing) HALT + HASS (Highly Accelerated Stress Screening) WHITE PAPER HALT + HASS LASER-MARKING SEALING BACKLIGHTING USB HALT + HASS Philosophy: If you don t have time to break it in the beginning you ll have plenty of time to fix it later.

2 Highly Accelerated Life Testing (HALT) and Highly Accelerated Stress Screening (HASS) Philosophy: If you don t have time to break it in the beginning you ll have plenty of time to fix it later The focus becomes high quality and unsurpassed product value through test, analysis, and re-engineering. It is amazing how some products hold up in the real world. Used over and over again they validate their purchase price by providing reliable service over the test of time. Maybe you have felt the heat of summer expended into the interior of your car on a hot day and watched the worst of the snowy winter work on the exterior of the same automobile yet that car still looks reasonably new; as if not affected. In reverse, it is such a disappointment when purchases tend to deteriorate much faster than they should. For most of us the operation of the failed device was under normal use and not abusive operation meaning nothing beyond what the manufacturer would consider ordinary operation was expected in its function. So some devices failed and some did not. Why is this so? What do some manufacturers perform in the way of testing / design services that distinguish them from others in the marketplace? Very likely the quality and ruggedness that you see in certain products is a result of some manufacturers performing HALT (Highly Accelerated Life Testing) and HASS (Highly Accelerated Stress Screening). These processes differ in focus from each other but both are used to uncover problems through the means of time compression. In other words, HALT and HASS use much higher stimuli than would exist in the field with the result of forcing failures or revealing design flaws in the device in significantly less time. This allows a company to see how their design would hold up over the years without having to wait that long. Defects are uncovered in the space of hours and observed with the purpose of making ongoing corrections. These defects are then monitored, classified according to their nature and corrected. Samples of the corrections that can be made are improvements to the assembly process, making mechanical revisions to the design to remove stress or inherent design flaws or revising components that are not performing according to their advertised potential. There is always the push for getting projects done in the least amount of time and refinements are made to streamline the development process as much as possible. In an effort to get a product to market expenses are watched very carefully by all concerned. This testing is one corner, however, that cannot be cut in an effort to meet budget or time considerations. The results of HALT / HASS testing have proved to be too valuable to most major manufacturers to skip; we have also seen the

3 value over time of checking the design of our products to make sure they perform to the satisfaction of our customers. Hence our statement, If you don t have time to break it in the beginning you ll have plenty of time to fix it in the future. Defining HALT / HASS and the Origins of These Testing Procedures As mentioned, HALT and HASS both act as time compression, stress testing but they differ in their focus. These two processes are closely aligned and used in tandem to ultimately determine if the device was designed correctly and is still being built properly but they are not performed at the same time with the same criteria. In HALT testing every stimulus that has potential effect to a product, whether it will be seen in the products operational life or not, is used to find the weak links in the design. The purpose is to find out how rugged the design is by taking the product or device to the point where it breaks and document the failures as they occur. The stimuli used for HALT testing may include all-axis impact vibration, broad range thermal cycling over a short period of time, electronic burn in of the components, over-voltage conditions, power or voltage cycling, humidity or all of the above being used together or in various combinations. These stresses are not necessarily meant to simulate the environment that the product will find in the field. The stimuli are stepped up to well beyond any field conditions until a flaw or multiple flaws are exposed and the design has reached its fundamental limits. Through this process the manufacturer knows the margin between the specified operational limits of the product and how far beyond that the device will actually go. Since any product will deteriorate over time, the importance of this test is also knowing how long the product life might be under normal operating conditions and how much abuse it will take in that amount of time. HALT testing is an extremely important part of the early development and manufacturing process. Most design processes are in a state of flux in the beginning but as the process and design develops, the product becomes more fixed and rigid. Its ability to change, and the cost of any change, becomes increasingly more difficult to make. Using the feedback generated by the HALT testing in the beginning allows the substitution of materials, components and improved process parameters in a timely fashion before the design becomes rigid and before costly failures are produced in the field. HASS differs from HALT in that it is a screening of the actual products being produced through manufacturing using a less stressful level of stimuli. We are not trying to break the product in this case but verify that the design is rugged enough to meet the actual specification limits agreed on by ourselves and our customer. In this testing a device, or several, are pulled out of production and run through a series of tests that simulate the highest possible stresses that the product will see often times exceeding the operational limits called out on the specification. Using the concept of time compression again, these tests show in a short amount of time that the product is operating the way it should, that it has an acceptable level of ruggedness and that there are no errors being introduced into the manufacturing process. There are times the manufacturing process strays or components are substituted due to obsolescence that were not reviewed properly. This in-process lot testing ensures that the process is continuously intact and that the product meets and exceeds specifications. It should be noted that HALT is required initially in the development process in order for the HASS testing to be properly performed. The HASS test is well below the limits of the products ruggedness and design but we first had to find and document these limits by means of the HALT process. One is dependant on the other. The process of design verification through accelerated life testing is not a recent event but has been performed since the early 1950 s beginning with the US military. Through a directive issued by our government, military vendors were required to improve the reliability of their products by applying a standard series of tests to their components. This was especially applicable to the military where components are required to withstand extreme field conditions and a wide variety of temperature variables as standard operating procedure. These tests directed the suppliers to stress their products beyond the specified limits of most environmental extremes to limits not seen before. This was to find out when and how their products would fail, but more importantly to use that information to make future products more robust. What used to be the requirement of an exclusive few dealing with the military is now the standard for many in the market place; both nationally and internationally. It is now done in order to meet customer quality expectations and to remain competitive in a global sense. The extremes of temperature, vibration and stress have been pushed out even farther than those standards of the past with the purpose of improving all designs beyond previous expectations thought feasible. The result has been that products continue to improve and the customer can expect quality at a level not found before.

4 HALT / HASS Testing at Advanced Input Systems and the Steps Involved uses a Thermotron AST chamber in our Coeur d Alene facility for both the HALT & HASS testing to subject the parts to stresses ensuring that a specific set of conditions will be replicated within a chambered environment to exact, repeatable conditions. Within this chamber products are submitted to the following conditions: rapid temperature fluctuations (extreme cold to high heat in a matter of seconds), sequential temperature step stresses, various voltage ranges, power cycling, vibration extremes or a combination of any of the above at the same time. chamber or by tracking field failure issues and their frequency. Again, the best mode is to find failures before they reach the consumer. 6. Document experiences: The goal is to not only capture the experiences of the testing as it relates one project, but to take all learned experiences and apply them to future product designs before they ever reach the HALT / HASS process. This is where design experiences snowball into better and better products as a result of testing feedback. The HALT / HASS process is used, as an example, to find some of the following flaws or problems: Mechanical defects / design flaws Solder quality issues Broken component leads Shorts between components Broken traces or wires Screws backed out / broken Electrical defects / design flaws Defective components not meeting spec Hidden stress points in the design Marginal circuit designs The basic steps in the HALT / HASS detection process 1. Precipitation: Changing a hidden, latent or undeveloped flaw into a developed and exposed flaw by the application of accelerated stresses in rapid temperature cycling, temperature extremes, voltage margining, vibration or a combination of all these items. This step is performed in the HALT / HASS chamber. 2. Detection: Once the flaw is developed after the HALT / HASS process, it is detected by means of visual, electrical or functional inspection. The flaw is documented and specifically stated for the next step involving evaluation. 3. Failure analysis: All causes and conditions are considered to the end that the reason for the failure is determined specifically. This becomes the root cause of the failure found in the testing chamber and is documented as such. 4. Corrective Action: As a result of determining the root cause changes are made to either the production process, the components or the mechanical design in order to remove the flaw found during testing from the design. 5. Verification: Follow up is necessary to verify that the root cause analysis and subsequent corrective action deemed necessary did in fact correct the problem found during the HALT / HASS process. This can be done through another round of testing within the For more information, call or visit W. Wilbur Avenue Coeur d Alene, ID USA sales@advanced-input.com

5 We make the input devices that control the OEM products that operate the world. HALT Defects By Environment Certain processes reveal defects more regularly than others. For instance notice below how important the vibration process is as an aspect of the overall testing. As referenced, HALT failures are discovered by percentage as follows: High Temperature Extreme (17%) Rapid Temperature Transitions (4%) Low Temperature Extreme (14%) Vibration (6 DoF) (45%) Combined Vibration with Rapid Temperature Transitions (20%) The Results of Testing and Determining the Need How has the process worked? In companies that use the HALT / HASS process, published studies indicate that field failures of products within the first year have dropped from an average of 10% to less than 1%. Finding failures early in the development process improves product quality without a doubt. The HALT / HASS process means that the customer doesn t have to wait for years to see how the product will perform. With this process, testing can be implemented that simulates years of functioning in the space of a few hours with the benefit of monitoring the results and corrections in that short time. The ultimate success of the testing is found within the individual company structure. It requires that both management and design engineering commit themselves to the results found during the testing. This means ensuring that HALT / HASS is not overlooked in a rush effort to get products to the marketplace. It also means the root cause of any defects, as well as their correction, are taken care of as soon as possible in the current design and documented for future designs or manufacturing processes. The end result is that new products will have the defects built out of them before the consumer ever sees them. Not every manufacturer can or will commit to this process. There are reasons for this. First, this is a process where you identify the problems up front and pro-actively fix them in the development phase. It is not free there is an internal cost for this effort in terms of man power, research and test equipment. Some manufacturers see this as either an unnecessary effort or extra cost that they don t want to incur. This can be either driven by the style of management inside the company or the actual cost of the product vs. the competition s cost. Secondly, to use this process you need to commit to wanting top quality in your products. Obviously some products do not have the luxury of adding cost for the purpose of increasing either longevity or ruggedness. The price of performing this process would increase the product cost and consumers may not be willing to pay for a more expensive item. The third item is if the value of the product is not increased by means of this testing, the issue of HALT and HASS may be irrelevant. If the device is used in a one time application, or has a very simple or non-critical usage, it may not be worth the extra cost. We use many items like this every day such as spoons, coffee stirrers and tissue paper where the use is not complicated and the difference in quality would not be enhanced by HALT / HASS.

6 Environmental stimuli available for testing in the HALT process: Takes the Risk Out of the Future by Testing Today If you need this early success in new products is it a risk to use a supplier that doesn t incorporate this testing in their product development? Is this a risk that you have to take? How do we know that our products are robust enough meet the conditions that they are expected to operate in? Is the customer or consumer expected to take this risk? is committed to the purpose of testing designs up front in the development process. Not only has it led to the increased reliability of products for our customers, but with an inhouse design engineering group and testing facility we have been able to capture the results for future projects. Many of our keyboards used around the world have proprietary design enhancements that have been the direct result of hours of investigation, effective root cause analysis and design enhancements all implemented into today s product improvements through the HALT / HASS process. Making it, breaking it, and fixing it in-house and before release cuts product failure by up to 90% and saves you time and money. As a leader in custom keyboard applications, would like an opportunity to meet your needs using our extensive engineering resources, proven innovative solutions, and HALT / HASS testing processes. For more information, call or visit Esterline Corporation. All rights reserved. Trademarks and trade names are property of their respective owners. reserves the right to make changes to products and services described herein without prior notice.